Spark-plug-testing device



Aug. 16, 1921. 1,639,603 F. W. GOWLAND SPARK PLUG TESTING DEVICE Filed Nov. '7. 1925 Patented Aug. 16, 1927.

rnnn 'WIL iAN GowIlANn, or PHI IPSBURG; PENNSYLVANIA, ASSIGNOR or ONE- HALF TO FRANK COEN' CROYLE, OF

P I-IILIIPSBUBG, PENNSYLVANIA.

sraax-rLoef'rns'riNe DEVICE.-

Application filed November 7 This invention relates toelectrical testing apparatus and has for its object the provislon of a novel device adapted to be engaged upon V spark plugs and Operable to short circuit a selected one or ones for the purpose of testing an engine for weak explosions, misfiring, knocks and other defects.

It is well known that it is a common practice among mechanicsto short-circuit a-plug or plugs by'means of a screw driver or the like which is simply brought into engagement with the central electrode of the plug and with a portion .of the engine, thedifferent plugs being shorted at different times in order to ascertain the conditions. This method is primitive and clumsy and frequently results in the loss of time besides not, being accurate.

It is with the above facts in View that I have designed the. present device which embodies movable elements engageable selectively with the central electrodes of spark plugs for short circuiting them,the arrange ment being such 'that the operators hands are left free, after setting the switches, so that he may do other things, it being moveover possible to short circuit a number of plugs at one time, which would obviously be impossible with the screw driver method.

Another object of the invention is to provide a device of this character which may. be mounted permanently upon the engine so as to be ready for instant use whenever necessary or desirable.

' of this character capable of being applied to plugs in pairs, adjustment being possible in accordance with ,the distance between the plugs.

An additional object is to provide a testing device of this character which will be simple and inexpensive in manufacture, easy to install and use, positive in action, efiic'ient and durable in service, and a general improvement in the art.

With the above and other objects and advantages in view, the invention consists in the details of construction and arrangement of parts to be hereinafter more fully described and claimed, and illustrated in the accompanying drawing in which:

Figure 1 is a side elevation of the device Still another object is to provide a device 7, 1925. semi No. 67,628.

applied to'a of spark plugs, one thereof being short circuited, I v p Figure 2 1s a plan view of the device alone with both switch me-mbers'in normal or inoperative. position,

Figure 3 is a longitudinal section, Figure 4 is a plan View of a modified form, and v the modification. 7

Referring more. particularly to the drawings the letter A designates a portion of the cylinder head of an engine and, B represents a pair of spark plugs screwed theres into. In carrying out the invention I pro-' vide an elongated strip 10 of suitable insulating material slotted at both ends .as

shown at 11 so i as to be engaged upon the; central electrodes G of the spark plugs prior to the engagement of the-binding nuts D clamp the strip in place. Located beneath and riveted or otherwise secured to the strip 10 is a metallic strip .12 formedwith upstanding ears 13 passing through suitable slots 141 in the strip 10 and carrying pivoted metal arms 15 equipped with handles 16 of insulating material. Slidably mounted through suitable holes at the center of the strips 10 and 12 is a plunger or stem 17 provided with heads 18 and 19 at its upper and lower ends, respectively, and encircled by a coil spring 20 which engages the plate 12 and the head 19 for holding the latter in contact with the cylinder head A. The pivoted arms 15 are shown in Figures 1 and 2 as vertically swingable so as to be capable of being brought into engagement with the binding nuts D.

Figure 5 is a longitudinal section through thereon, these nuts consequently acting to In the operation, it is apparent that by swinging any arm 15 into engagement with the adjacent spark plug, it may be short circuited. In actual testing it is of course apparent that when a plug is shorted and the engine does not slow down it is safe to assume that that particular plug is not functioning. It is also known that certain knocks are more readily detachable when the plug for that particular cylinder is not firing. In case of a multicylinder motor it is obvious that by shorting the various plugs at different times an efficient test may be made to determine just what conditions e2:- ist. Clearly when the arms 15 are swung inwardly or toward each other as shown in Figure 2 they will have no efiect whatsoever onathe plu 's and the device may consequently be left permanently in position ready for instant use.

In Figures 4 and 5 I have illustrated a slight modification in which I have disclosed contact arms 21 pivoted at 22 and swlngable horizontally to be brought into engagement with the central electrode or binding 'nut, as

may bepreferredythe arms 21 being preferably resilient so as to remain in engagement with the plug 1ft desired. This form operates in exactly the same manner as the other, the sole difference being the mounting of the contact arms.

From the foregoing description and a study of the drawings it will be apparent that I have thus provided a simply constructed lnexpenslve and hlghly eiliclent device for the purpose specified which will satisfactorily perform all the functions for which it is intended.

lVhile I'have shown and described a preferred embodiment of the invention it should be understood that I reserve the right to make such changes in the-form, construction and arrangement of parts as will not de part from the spirit of the invention or the scope of the subjoined claims.

Having thus described the invention I claim:

1. A device of the character described comprising an elongated supporting member of insulating material slotted at its ends for engagement upon the central electrodes of adjacent spark plugs a metallic member secured to the underside of said insulating strip and having ears located above the strip, aspring pressed plunger slidable through bothstrips and in electrical contact with the metallic member and adapted to engage the engine to provide a ground connection and contact arms equipped with handles and pivotally mounted on said ears to be capable oi swinging into engagement with the central electrodes of the spark plugs.

' 2. A sparkplug tester comprising a metal FRED WILLIAM GOWLAND, V 

